Abstract: Provided are a chromium catalyst precursor, an ethylene oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same. More particularly, a chromium catalyst precursor which may oligomerize ethylene with high activity and high selectivity in spite of not using methylaluminoxane (MAO) or modified-methylaluminoxane (MMAO), an oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same are provided.

Abstract: Provided is a method of manufacturing a gold (Au) thin film on a dielectric surface by using an electroless-plating method, the method including: manufacturing a reaction mixture by adding an Au chloride compound and an alkaline compound to an alcohol-water mixed solution; and forming an Au thin film by putting a substrate in the reaction mixture and stirring the reaction mixture. Accordingly, compounds that are relatively low toxic may be used as raw materials, and an Au thin film having a surface enhancement Raman scattering (SERS) effect may be conveniently and stably formed on a dielectric surface without having to use expensive additional equipment, such as a vacuum device.

Abstract: A penis erection stabilizer wherein a through-hole is defined through a center portion of a stabilizer body having a cylindrical configuration so that the penis can be inserted through the through-hole, and a small diameter portion having a diameter less than that of the through-hole is formed at a front end of the through-hole. According to the present invention, advantages are conferred in that the penis erection stabilizer has a single body and a small diameter portion is formed at the front end of a through-hole so that the blood can be easily supplied to the penis and the discharge of the blood from the penis can be maximally retarded, thereby maintaining the erected state of the penis for a time sufficient for the completion of the sexual act.

Abstract: A penis erection stabilizer wherein a through-hole is defined through a center portion of a stabilizer body having a cylindrical configuration so that the penis can be inserted through the through-hole, and a small diameter portion having a diameter less than that of the through-hole is formed at a front end of the through-hole. According to the present invention, advantages are conferred in that the penis erection stabilizer has a single body and a small diameter portion is formed at the front end of a through-hole so that the blood can be easily supplied to the penis and the discharge of the blood from the penis can be maximally retarded, thereby maintaining the erected state of the penis for a time sufficient for the completion of the sexual act.